Answer: PC × PD.
- A PC × PD
- B (PC + PD)/2
- C PC² + PD²
- D PC - PD
Correct answer: A. PC × PD
Explanation: Intersecting chords theorem: triangles PAC and PDB are similar (angles in same segment). So PA/PC=PD/PB, giving PA×PB=PC×PD. This product equals the absolute value of the power of point P w.r.t. the circle. Ans: PC×PD.
Three standard 3D solids and their key formulas: a cylinder's volume scales with the full height, a cone's volume is exactly one-third of the cylinder with the same base and height, and a sphere's volume and surface area both follow distinct r-based formulas worth memorising separately.
Concept context
Perimeters, areas, and volumes of 2D and 3D shapes